<?php 
    // define a user space function
    function some_function($param) {
        echo("user space function called with $param\n");
    }

    // example input
    $input = array(
        'x' => 10,
        'y' => 20,
        'z' => 30
    );

    example_function($input, function($param1, $param2) {
        echo ("lambda function called with param $param2 \n");
    });